Only the most extreme authoritarians will attempt to silence all dissonance. Most will have a controlled opposition as the illusion of choice and a release valve for anger.

Russia, for example, runs elections and up until recently allowed the opposing party on the ballot. Same with Belarus. China and Iran also have elections, but the candidates are vetted through the state party. I know now Americans from each of these countries (except Iran). One who still votes in the Belarus elections even though they know it won't change anything.

NK is about the only modern regime I know where all opposition is punished. And even then, there's been reports of a loosening of enforcement.